“As long as Europe’s borders are not protected by our partners, France will re-establish real controls at its borders,” Mr Fillon tweeted.

In a break with EU orthodoxy, Mr Fillon said he would ignore the Schengen open borders agreement, seen by many western European leaders as non-negotiable, although several countries have restored some limited border controls to cope with the migration crisis.

Mr Fillon, whose main rival in the election this spring is expected to be Marine Le Pen, the anti-immigration hard-Right leader, made the comment a day after he rejected the open-door policy of Angela Merkel, the German chancellor.

After more than an hour of talks with Mrs Merkel, Mr Fillon said France could accept no more refugees and would “make a different choice” from Germany under his leadership.

“Schengen must be reformed,” he said. “Free movement in Europe must have a non-negotiable counterbalance: systematic controls at the external borders.”

But he said France and Germany should still agree on a “common asylum policy” — a remark that was attacked by Ms Le Pen’s deputy, Florian Philippot. He said Mr Fillon had “sworn allegiance to Merkel and her insane migration policy”.

In an apparent response, Mr Fillon seemed to acknowledge that there was little hope of other European countries policing their borders adequately and France would therefore step up its own border controls.